After holding back on the jokes while in China, it didn't take Prime Minister John Key long to crack once he was back among New Zealanders.

Mr Key spent a day in Hong Kong meeting its chief executive and attending tourism promotion events.

Speaking to expat Kiwis at the plush Hong Kong Country Club, Mr Key reprised them of his visit to China, including the deal to allow direct currency conversion between the NZ dollar and China renminbi.

"You can now convert New Zealand dollars into renminbi, if you are of such a mind to do so. So, life after politics, I might go back to the foreign exchange markets and smack around the renminbi. Maybe not."


Mr Key also spoke about the Hong Kong Sevens, due to take place next weekend. He said the only time he had been was "a very messy affair, I have to say."

"I did meet with Cathay Pacific this afternoon who said I'm the only foreigner in the world who's come to Hong Kong the week before the Sevens."

Mr Key will travel to the Hague today for the Nuclear Security Summit.

He and wife Bronagh spent the last few days in London with their daughter Steffi for a surprise celebration for her 21st birthday.

Mr Key was due to go to Russia between his visit to China and the Summit but that was scrapped after New Zealand called a halt to its free trade agreement talks because of Russia's actions in Crimea.

The summit in the Netherlands will be the third meeting of leaders of about 53 countries invited to take part by US President Barack Obama. Obama convened the summit to address the safe storage and disposal of nuclear materials so they can not be used for terrorism or cause an environmental disaster.

Mr Obama invited New Zealand to take part alongside the nuclear powers because of its nuclear-free credentials.

The summit also affords an opportunity for the invited leaders to meet to discuss other matters on the sidelines. Ukraine is expected to dominate. Mr Key said he did expect to talk with Mr Obama at some point. He would hold meetings German's Chancellor Angela Merkel, Canada's Stephen Harper and a dinner with the Netherlands' Mark Rutte. He would also catch up with United Kingdom Prime Minister David Cameron over a drink. He will also see China's President Xu Jinping again, whom he met with while in China last week.


Mr Key said he would continue to make New Zealand's case for votes to secure the Security Council seat which will be voted on later this year at the UN General Assembly.

Mr Key said the aim of the summit was a long term issue, but was also of global significance given the implications of a nuclear spill.